108-904 3/4" SILLCOCK VACUUM BREAKER | Fits any 3/4 in hose thread outlet. Prevents back siphoning of contaminated water, protection for portable hoses connected to hose thread faucets. Break-off attachment screw for permanent installation with no plumbing changes. Hose threads comply with ANSI B1.20.7, ASSE 1019 approved, UPC, Canadian UPC approved.